Research on Natural Gas Leakage Diffusion of Urban Underground Pipeline and its Explosion Hazard

For the risk of gas leakage and explosion that may occur during the serviceability of urban natural gas pipeline, based on the numerical simulation conducted by FLACS, the gas leakage, explosion and disaster risk under the different speed of wind are mainly studied with local climate characteristics for actual urban street. The results show that the wind speed has an obvious effect on the gas leakage and diffusion, the deviation of gas leakage direction is not obvious for the smaller speed of wind at the initial stage, the horizontal diffusion range gradually increases with the increase of wind speed, while the vertical diffusion range gradually decreases, and the volume of gas at the limit concentration of combustion and explosion gradually decreases. In urban buildings, the overpressure load of higher buildings is lower. After the explosion, the peak overpressure at the same monitoring point decreases with the increase of wind speed. With the increase of distance from the building to the explosion location, the overpressure load on the building decreases and the oscillation effect of overpressure load is relatively gentle. The thermal radiation after burning has great influence on the surrounding buildings and downwind position, especially the buildings around the leakage point.